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Peraro MD, van der Goot FG. Pore-forming toxins: ancient, but never really out of fashion. Nat Rev Microbiol 2015; 14:77-92. [DOI: 10.1038/nrmicro.2015.3] [Citation(s) in RCA: 476] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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52
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Risco-Castillo V, Topçu S, Marinach C, Manzoni G, Bigorgne A, Briquet S, Baudin X, Lebrun M, Dubremetz JF, Silvie O. Malaria Sporozoites Traverse Host Cells within Transient Vacuoles. Cell Host Microbe 2015; 18:593-603. [DOI: 10.1016/j.chom.2015.10.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 08/31/2015] [Accepted: 10/02/2015] [Indexed: 12/28/2022]
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53
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Wirth CC, Bennink S, Scheuermayer M, Fischer R, Pradel G. Perforin-like protein PPLP4 is crucial for mosquito midgut infection by Plasmodium falciparum. Mol Biochem Parasitol 2015; 201:90-9. [PMID: 26166358 DOI: 10.1016/j.molbiopara.2015.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 02/05/2023]
Abstract
The genomes of Plasmodium parasites encode for five perforin-like proteins, PPLP1-5, and four of them have previously been demonstrated to be involved in disruption of host cell barriers. We now show that the fifth perforin, PPLP4, is crucial for infection of the mosquito vector by Plasmodium falciparum parasites. PPLP4 is expressed in the blood and mosquito midgut stages in granular structures. In gametocytes, PPLP4 expression is specific to the female gender, while ookinetes show a PPLP4 localization at the apical pole. Gene disruption of pplp4 results in no phenotypical change during blood stage replication, gametocyte development or gametogenesis, while mosquitoes fed with PPLP4-deficient gametocytes display a severe reduction in oocyst numbers, and an accumulation of ookinetes in the mosquito midguts was observed. In conclusion, we propose an essential role for PPLP4 in infection of the mosquito midgut, presumably by mediating ookinete traversal through the midgut epithelium.
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Affiliation(s)
- Christine C Wirth
- Cellular and Applied Infection Biology Section, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sandra Bennink
- Cellular and Applied Infection Biology Section, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Matthias Scheuermayer
- Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Str. 2/D15, 97080 Würzburg, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstr. 6, 52074 Aachen, Germany
| | - Gabriele Pradel
- Cellular and Applied Infection Biology Section, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstr. 6, 52074 Aachen, Germany.
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Andreadaki M, Mollenkopf HJ, Nika F, Brady D, Tewari R, Matuschewski K, Siden-Kiamos I. Global expression profiling reveals shared and distinct transcript signatures in arrested act2(−) and CDPK4(−) Plasmodium berghei gametocytes. Mol Biochem Parasitol 2015. [DOI: 10.1016/j.molbiopara.2015.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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55
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The Apicomplexan CDC/MACPF-like pore-forming proteins. Curr Opin Microbiol 2015; 26:48-52. [PMID: 26025132 DOI: 10.1016/j.mib.2015.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/01/2015] [Accepted: 05/06/2015] [Indexed: 11/22/2022]
Abstract
Pore-forming proteins (PFPs) encompass a broad family of proteins that are used for virulence or immune defense. Members of the cholesterol-dependent cytolysins (CDCs) and membrane attack complex/perforin (MACPF) family of PFPs form large β-barrel pores in the membrane. The CDC/MACPF proteins contain a characteristic four-stranded β-sheet that is flanked by two α-helical bundles, which unfold to form two transmembrane β-hairpins. Apicomplexan eukaryotic parasites express CDC/MACPFs termed perforin-like proteins (PLPs). Here we review recent studies that provide key insights into the assembly and regulation of the Apicomplexan PLP (ApiMACPF) molecular pore-forming mechanisms, which are necessary for the osmotically driven rupture of the parasitophorous vacuole and host cell membrane, and cell traversal by these parasites.
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Kaneko I, Iwanaga S, Kato T, Kobayashi I, Yuda M. Genome-Wide Identification of the Target Genes of AP2-O, a Plasmodium AP2-Family Transcription Factor. PLoS Pathog 2015; 11:e1004905. [PMID: 26018192 PMCID: PMC4446032 DOI: 10.1371/journal.ppat.1004905] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 04/21/2015] [Indexed: 12/20/2022] Open
Abstract
Stage-specific transcription is a fundamental biological process in the life cycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation and belong to the only known family of transcription factors in Plasmodium parasites. Comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific transcriptional regulation and stage-specific parasite development. AP2-O is an AP2 family transcription factor that is expressed in the mosquito midgut-invading stage, called the ookinete, and is essential for normal morphogenesis of this stage. In this study, we identified the genome-wide target genes of AP2-O by chromatin immunoprecipitation-sequencing and elucidate how this AP2 family transcription factor contributes to the formation of this motile stage. The analysis revealed that AP2-O binds specifically to the upstream genomic regions of more than 500 genes, suggesting that approximately 10% of the parasite genome is directly regulated by AP2-O. These genes are involved in distinct biological processes such as morphogenesis, locomotion, midgut penetration, protection against mosquito immunity and preparation for subsequent oocyst development. This direct and global regulation by AP2-O provides a model for gene regulation in Plasmodium parasites and may explain how these parasites manage to control their complex life cycle using a small number of sequence-specific AP2 transcription factors. Although malarial parasites have a complex life cycle, they harbor only 30 transcription factors in their genome. The majority of these transcription factors belong to a single family referred to as the AP2 family. Our previous study suggested that stage-specific AP2 family transcription factors have critical roles in maintaining the Plasmodium parasite life cycle. However, it remains fairly elusive as to how these transcription factors regulate each stage. AP2-O is an AP2 family transcription factor that is expressed during the mosquito midgut-invading stage, the ookinete, and is essential for normal development of this stage. In the present study, we identified the entire set of AP2-O target genes to elucidate how this AP2 family transcription factor contributes to the formation of this stage. Our results showed that AP2-O directly regulates 10% of the parasite genome and is involved in the whole process of mosquito midgut-invasion by ookinetes. The global and comprehensive regulation by the AP2 family transcription factor that we revealed provides a model for transcriptional regulation of this parasite and may explain how malarial parasites regulate their complex life cycle using a small number of sequence-specific transcription factors.
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Affiliation(s)
- Izumi Kaneko
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Shiroh Iwanaga
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Tomomi Kato
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Issei Kobayashi
- Core-Lab, Graduate School of Regional Innovation Studies, Mie University, Tsu, Mie, Japan
| | - Masao Yuda
- Department of Medical Zoology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- * E-mail:
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57
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Dantzler KW, Ravel DB, Brancucci NM, Marti M. Ensuring transmission through dynamic host environments: host-pathogen interactions in Plasmodium sexual development. Curr Opin Microbiol 2015; 26:17-23. [PMID: 25867628 DOI: 10.1016/j.mib.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/09/2015] [Indexed: 01/08/2023]
Abstract
A renewed global commitment to malaria elimination lends urgency to understanding the biology of Plasmodium transmission stages. Recent progress toward uncovering the mechanisms underlying Plasmodium falciparum sexual differentiation and maturation reveals potential targets for transmission-blocking drugs and vaccines. The identification of parasite factors that alter sexual differentiation, including extracellular vesicles and a master transcriptional regulator, suggest that parasites make epigenetically controlled developmental decisions based on environmental cues. New insights into sexual development, especially host cell remodeling and sequestration in the bone marrow, highlight open questions regarding parasite homing to the tissue, transmigration across the vascular endothelium, and maturation in the parenchyma. Novel molecular and translational tools will provide further opportunities to define host-parasite interactions and design effective transmission-blocking therapeutics.
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Affiliation(s)
- Kathleen W Dantzler
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Deepali B Ravel
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Nicolas Mb Brancucci
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
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58
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Burda PC, Roelli MA, Schaffner M, Khan SM, Janse CJ, Heussler VT. A Plasmodium phospholipase is involved in disruption of the liver stage parasitophorous vacuole membrane. PLoS Pathog 2015; 11:e1004760. [PMID: 25786000 PMCID: PMC4364735 DOI: 10.1371/journal.ppat.1004760] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/22/2015] [Indexed: 11/18/2022] Open
Abstract
The coordinated exit of intracellular pathogens from host cells is a process critical to the success and spread of an infection. While phospholipases have been shown to play important roles in bacteria host cell egress and virulence, their role in the release of intracellular eukaryotic parasites is largely unknown. We examined a malaria parasite protein with phospholipase activity and found it to be involved in hepatocyte egress. In hepatocytes, Plasmodium parasites are surrounded by a parasitophorous vacuole membrane (PVM), which must be disrupted before parasites are released into the blood. However, on a molecular basis, little is known about how the PVM is ruptured. We show that Plasmodium berghei phospholipase, PbPL, localizes to the PVM in infected hepatocytes. We provide evidence that parasites lacking PbPL undergo completely normal liver stage development until merozoites are produced but have a defect in egress from host hepatocytes. To investigate this further, we established a live-cell imaging-based assay, which enabled us to study the temporal dynamics of PVM rupture on a quantitative basis. Using this assay we could show that PbPL-deficient parasites exhibit impaired PVM rupture, resulting in delayed parasite egress. A wild-type phenotype could be re-established by gene complementation, demonstrating the specificity of the PbPL deletion phenotype. In conclusion, we have identified for the first time a Plasmodium phospholipase that is important for PVM rupture and in turn for parasite exit from the infected hepatocyte and therefore established a key role of a parasite phospholipase in egress. Leaving their host cell is a crucial process for intracellular pathogens, allowing successful infection of other cells and thereby spreading of infection. Plasmodium parasites infect hepatocytes and red blood cells, and inside these cells they are contained within a vacuole like many other intracellular pathogens. Before parasites can infect other cells, the surrounding parasitophorous vacuole membrane (PVM) needs to be ruptured. However, little is known about this process on a molecular level and Plasmodium proteins mediating lysis of the PVM during parasite egress have not so far been identified. In this study, we characterize a Plasmodium phospholipase and show that it localizes to the PVM of parasites within hepatocytes. We demonstrate that parasites lacking this protein have a defect in rupture of the PVM and thereby in host cell egress. In conclusion, our study shows for the first time that a phospholipase plays a role in PVM disruption of an intracellular eukaryotic parasite.
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Affiliation(s)
- Paul-Christian Burda
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular Biology, University of Bern, Bern, Switzerland
- * E-mail:
| | | | - Marco Schaffner
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Shahid M. Khan
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Chris J. Janse
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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59
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Sinden RE. The cell biology of malaria infection of mosquito: advances and opportunities. Cell Microbiol 2015; 17:451-66. [PMID: 25557077 PMCID: PMC4409862 DOI: 10.1111/cmi.12413] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/12/2014] [Accepted: 12/24/2014] [Indexed: 01/01/2023]
Abstract
Recent reviews (Feachem et al.; Alonso et al.) have concluded that in order to have a sustainable impact on the global burden of malaria, it is essential that we knowingly reduce the global incidence of infected persons. To achieve this we must reduce the basic reproductive rate of the parasites to < 1 in diverse epidemiological settings. This can be achieved by impacting combinations of the following parameters: the number of mosquitoes relative to the number of persons, the mosquito/human biting rate, the proportion of mosquitoes carrying infectious sporozoites, the daily survival rate of the infectious mosquito and the ability of malaria-infected persons to infect mosquito vectors. This paper focuses on our understanding of parasite biology underpinning the last of these terms: infection of the mosquito. The article attempts to highlight central issues that require further study to assist in the discovery of useful transmission-blocking measures.
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Affiliation(s)
- R E Sinden
- Department of Life Sciences, Imperial College London and the Jenner Institute, The University of Oxford, Oxford, UK
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60
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Nikolaeva D, Draper SJ, Biswas S. Toward the development of effective transmission-blocking vaccines for malaria. Expert Rev Vaccines 2015; 14:653-80. [PMID: 25597923 DOI: 10.1586/14760584.2015.993383] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The continued global burden of malaria can in part be attributed to a complex lifecycle, with both human hosts and mosquito vectors serving as transmission reservoirs. In preclinical models of vaccine-induced immunity, antibodies to parasite sexual-stage antigens, ingested in the mosquito blood meal, can inhibit parasite survival in the insect midgut as judged by ex vivo functional studies such as the membrane feeding assay. In an era of renewed political momentum for malaria elimination and eradication campaigns, such observations have fueled support for the development and implementation of so-called transmission-blocking vaccines. While leading candidates are being evaluated using a variety of promising vaccine platforms, the field is also beginning to capitalize on global '-omics' data for the rational genome-based selection and unbiased characterization of parasite and mosquito proteins to expand the candidate list. This review covers the progress and prospects of these recent developments.
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Affiliation(s)
- Daria Nikolaeva
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
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61
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Olivieri A, Bertuccini L, Deligianni E, Franke-Fayard B, Currà C, Siden-Kiamos I, Hanssen E, Grasso F, Superti F, Pace T, Fratini F, Janse CJ, Ponzi M. Distinct properties of the egress-related osmiophilic bodies in male and female gametocytes of the rodent malaria parasitePlasmodium berghei. Cell Microbiol 2014; 17:355-68. [DOI: 10.1111/cmi.12370] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 08/20/2014] [Accepted: 09/08/2014] [Indexed: 01/09/2023]
Affiliation(s)
- Anna Olivieri
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
| | - Lucia Bertuccini
- Istituto Superiore di Sanità; Dipartimento di Tecnologia e Salute; Rome Italy
| | - Elena Deligianni
- Institute of Molecular Biology and Biotechnology, FORTH; Heraklion Greece
| | - Blandine Franke-Fayard
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases; Leids Universitair Medisch Centrum (LUMC); Leiden The Netherlands
| | - Chiara Currà
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
| | - Inga Siden-Kiamos
- Institute of Molecular Biology and Biotechnology, FORTH; Heraklion Greece
| | - Eric Hanssen
- Bio21 Molecular Science and Biotechnology Institute, Electron Microscopy Unit and Department of Biochemistry and Molecular Biology; University of Melbourne; Melbourne Australia
| | - Felicia Grasso
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
| | - Fabiana Superti
- Istituto Superiore di Sanità; Dipartimento di Tecnologia e Salute; Rome Italy
| | - Tomasino Pace
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
| | - Federica Fratini
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
| | - Chris J. Janse
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases; Leids Universitair Medisch Centrum (LUMC); Leiden The Netherlands
| | - Marta Ponzi
- Istituto Superiore di Sanità, Dipartimento di Malattie Infettive; Parassitarie ed Immunomediate; Rome Italy
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Akinosoglou KA, Bushell ESC, Ukegbu CV, Schlegelmilch T, Cho JS, Redmond S, Sala K, Christophides GK, Vlachou D. Characterization of Plasmodium developmental transcriptomes in Anopheles gambiae midgut reveals novel regulators of malaria transmission. Cell Microbiol 2014; 17:254-68. [PMID: 25225164 PMCID: PMC4371638 DOI: 10.1111/cmi.12363] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 08/27/2014] [Accepted: 09/08/2014] [Indexed: 12/24/2022]
Abstract
The passage through the mosquito is a major bottleneck for malaria parasite populations and a target of interventions aiming to block disease transmission. Here, we used DNA microarrays to profile the developmental transcriptomes of the rodent malaria parasite Plasmodium berghei in vivo, in the midgut of Anopheles gambiae mosquitoes, from parasite stages in the midgut blood bolus to sporulating oocysts on the basal gut wall. Data analysis identified several distinct transcriptional programmes encompassing genes putatively involved in developmental processes or in interactions with the mosquito. At least two of these programmes are associated with the ookinete development that is linked to mosquito midgut invasion and establishment of infection. Targeted disruption by homologous recombination of two of these genes resulted in mutant parasites exhibiting notable infection phenotypes. GAMER encodes a short polypeptide with granular localization in the gametocyte cytoplasm and shows a highly penetrant loss-of-function phenotype manifested as greatly reduced ookinete numbers, linked to impaired male gamete release. HADO encodes a putative magnesium phosphatase with distinctive cortical localization along the concave ookinete periphery. Disruption of HADO compromises ookinete development leading to significant reduction of oocyst numbers. Our data provide important insights into the molecular framework underpinning Plasmodium development in the mosquito and identifies two genes with important functions at initial stages of parasite development in the mosquito midgut.
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63
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Suaréz-Cortés P, Silvestrini F, Alano P. A fast, non-invasive, quantitative staining protocol provides insights in Plasmodium falciparum gamete egress and in the role of osmiophilic bodies. Malar J 2014; 13:389. [PMID: 25274542 PMCID: PMC4194377 DOI: 10.1186/1475-2875-13-389] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/27/2014] [Indexed: 12/23/2022] Open
Abstract
Background Ability of Plasmodium falciparum gametocytes to become extracellular during gametogenesis in the mosquito midgut is a key step of the parasite life cycle. Reliable and quantitative measurement of the efficiency of gamete egress is currently constrained by the fact that this phenomenon is usually observed and quantified in vitro either by live microscopy, by statistically limited ultrastructural analysis or by surface antibody-based protocols which can interfere with this fast and complex cellular process. Methods A protocol was developed based on fluorescent wheat germ agglutinin (WGA) surface staining of erythrocytes containing mature P. falciparum gametocytes. After a single centrifugation step and within minutes from the induction of gametogenesis, the activated gametes can be inspected for presence or absence of the fluorescent WGA staining of the host erythrocyte membrane and scored respectively as intracellular or emerged from the erythrocyte. Results Gametogenesis and gamete egress from WGA surface stained, infected erythrocytes occur with normal kinetics and efficiencies. Quantitative measurements of gamete egress can be obtained in live and in paraformaldehyde-fixed cells, which validates this protocol as a suitable tool both for live imaging studies and for higher throughput applications. The protocol was used here to provide functional information on the ability of gametes to egress through a single exit point induced in the host red blood cell membrane, and to re-analyse the phenotype of Pfg377- and osmiophilic body-defective gametes, suggesting that such parasite components are not directly involved in disruption and shedding of the erythrocyte membrane in female gamete egress. Conclusions The development of a reliable, fast, non-invasive and quantitative protocol to finely describe and to measure efficiency of P. falciparum gamete egress is a significant improvement in the tools for functional studies on this key process of the parasite life cycle. This protocol can be used to investigate the molecular mechanisms underlying gamete egress and its adaptation to high throughput applications will enable identification of transmission blocking inhibitors.
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Affiliation(s)
| | | | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n,299, 00161 Roma, Italy.
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64
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Wirth CC, Glushakova S, Scheuermayer M, Repnik U, Garg S, Schaack D, Kachman MM, Weißbach T, Zimmerberg J, Dandekar T, Griffiths G, Chitnis CE, Singh S, Fischer R, Pradel G. Perforin-like protein PPLP2 permeabilizes the red blood cell membrane during egress of Plasmodium falciparum gametocytes. Cell Microbiol 2014; 16:709-33. [PMID: 24602217 PMCID: PMC4312913 DOI: 10.1111/cmi.12288] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/17/2014] [Accepted: 02/21/2014] [Indexed: 12/18/2022]
Abstract
Egress of malaria parasites from the host cell requires the concerted rupture of its enveloping membranes. Hence, we investigated the role of the plasmodial perforin-like protein PPLP2 in the egress of Plasmodium falciparum from erythrocytes. PPLP2 is expressed in blood stage schizonts and mature gametocytes. The protein localizes in vesicular structures, which in activated gametocytes discharge PPLP2 in a calcium-dependent manner. PPLP2 comprises a MACPF domain and recombinant PPLP2 has haemolytic activities towards erythrocytes. PPLP2-deficient [PPLP2(−)] merozoites show normal egress dynamics during the erythrocytic replication cycle, but activated PPLP2(−) gametocytes were unable to leave erythrocytes and stayed trapped within these cells. While the parasitophorous vacuole membrane ruptured normally, the activated PPLP2(−) gametocytes were unable to permeabilize the erythrocyte membrane and to release the erythrocyte cytoplasm. In consequence, transmission of PPLP2(−) parasites to the Anopheles vector was reduced. Pore-forming equinatoxin II rescued both PPLP2(−) gametocyte exflagellation and parasite transmission. The pore sealant Tetronic 90R4, on the other hand, caused trapping of activated wild-type gametocytes within the enveloping erythrocytes, thus mimicking the PPLP2(−) loss-of-function phenotype. We propose that the haemolytic activity of PPLP2 is essential for gametocyte egress due to permeabilization of the erythrocyte membrane and depletion of the erythrocyte cytoplasm.
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Affiliation(s)
- Christine C Wirth
- Institute of Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
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65
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Tavares J, Amino R, Ménard R. The role of MACPF proteins in the biology of malaria and other apicomplexan parasites. Subcell Biochem 2014; 80:241-253. [PMID: 24798015 DOI: 10.1007/978-94-017-8881-6_12] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Apicomplexans are eukaryotic parasites of major medical and veterinary importance. They have complex life cycles through frequently more than one host, interact with many cell types in their hosts, and can breach host cell membranes during parasite traversal of, or egress from, host cells. Some of these parasites make a strikingly heavy use of the pore-forming MACPF domain, and encode up to 10 different MACPF domain-containing proteins. In this chapter, we focus on the two most studied and medically important apicomplexans, Plasmodium and Toxoplasma, and describe the known functions of their MACPF polypeptide arsenal. Apicomplexan MACPF proteins appear to be involved in a variety of membrane-damaging events, making them an attractive model to dissect the structure-function relationships of the MACPF domain.
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Affiliation(s)
- Joana Tavares
- Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Département de Parasitologie et Mycologie, 28 rue du Docteur Roux, 75015, Paris, France
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66
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Blackman MJ, Carruthers VB. Recent insights into apicomplexan parasite egress provide new views to a kill. Curr Opin Microbiol 2013; 16:459-64. [PMID: 23725669 PMCID: PMC3755044 DOI: 10.1016/j.mib.2013.04.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 04/23/2013] [Accepted: 04/25/2013] [Indexed: 01/20/2023]
Abstract
A hallmark of apicomplexan pathogens such as Plasmodium, Toxoplasma and Cryptosporidium is that they invade, replicate within, and then egress from their host cells. Egress usually results in lysis of the host cell, with deleterious consequences for the host. In the case of malaria, for example, much of the disease pathology is associated with cyclical waves of host erythrocyte destruction. This review highlights recent advances in mapping the signaling pathways that lead to egress and the parasite molecules involved in responding to and transmitting those signals. The review also discusses new findings for effector molecules that mediate disruption of the bounding membranes that enclose the intracellular parasite and the manner in which membrane rupture occurs to finally release invasive forms of the parasite.
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Affiliation(s)
- Michael J. Blackman
- Division of Parasitology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | - Vern B. Carruthers
- Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620
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Ngwa CJ, Scheuermayer M, Mair GR, Kern S, Brügl T, Wirth CC, Aminake MN, Wiesner J, Fischer R, Vilcinskas A, Pradel G. Changes in the transcriptome of the malaria parasite Plasmodium falciparum during the initial phase of transmission from the human to the mosquito. BMC Genomics 2013; 14:256. [PMID: 23586929 PMCID: PMC3640944 DOI: 10.1186/1471-2164-14-256] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 04/01/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The transmission of the malaria parasite Plasmodium falciparum from the human to the mosquito is mediated by dormant sexual precursor cells, the gametocytes, which become activated in the mosquito midgut. Because gametocytes are the only parasite stages able to establish an infection in the mosquito, they play a crucial role in spreading the tropical disease. The human-to-mosquito transmission triggers important molecular changes in the gametocytes, which initiate gametogenesis and prepare the parasite for life-cycle progression in the insect vector. RESULTS To better understand gene regulations during the initial phase of malaria parasite transmission, we focused on the transcriptome changes that occur within the first half hour of parasite development in the mosquito. Comparison of mRNA levels of P. falciparum gametocytes before and 30 min following activation using suppression subtractive hybridization (SSH) identified 126 genes, which changed in expression during gametogenesis. Among these, 17.5% had putative functions in signaling, 14.3% were assigned to cell cycle and gene expression, 8.7% were linked to the cytoskeleton or inner membrane complex, 7.9% were involved in proteostasis and 6.4% in metabolism, 12.7% were cell surface-associated proteins, 11.9% were assigned to other functions, and 20.6% represented genes of unknown function. For 40% of the identified genes there has as yet not been any protein evidence.For a subset of 27 genes, transcript changes during gametogenesis were studied in detail by real-time RT-PCR. Of these, 22 genes were expressed in gametocytes, and for 15 genes transcript expression in gametocytes was increased compared to asexual blood stage parasites. Transcript levels of seven genes were particularly high in activated gametocytes, pointing at functions downstream of gametocyte transmission to the mosquito. For selected genes, a regulated expression during gametogenesis was confirmed on the protein level, using quantitative confocal microscopy. CONCLUSIONS The obtained transcriptome data demonstrate the regulations of gene expression immediately following malaria parasite transmission to the mosquito. Our findings support the identification of proteins important for sexual reproduction and further development of the mosquito midgut stages and provide insights into the genetic basis of the rapid adaption of Plasmodium to the insect vector.
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Affiliation(s)
- Che Julius Ngwa
- Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany
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